US1773172A

US1773172A - Gyroscopic direction finder

Info

Publication number: US1773172A
Application number: US678096A
Authority: US
Inventors: Davis Arthur Patterson
Original assignee: Individual
Current assignee: Individual
Priority date: 1923-12-03
Filing date: 1923-12-03
Publication date: 1930-08-19
Anticipated expiration: 1947-08-19

Description

rant-r2 1 mg. 1'9, 1936. A; P. DAvfs GYROSCbPIC DIRECTION FINDER Filed Dec. 3, 1923 3 Sheets-Sheet 1 INVENTOR m ATTORNEYS Aug.T9, 1930. A. P. DAVIS I ,1

GYROSCOPIC DIRECTION FINDER Filed Dec. 3, 1923 3 Sheets-Sheet 2 'INVENTOR L M 4 'K BY flaw/12 94 TTORNEY$ Aug. 19, 1930. Y DAVIS 1,773,172

GYHOSCOPIC DIRECTION FINDER Filed Bag. 3, v1925 3 Sheets-Sheet 3 Patented Aug. 19, 1930 ARTHUR PATTERSON DAVIS, OF NEW YOkK, N. Y.

GYBOSGOPIC DIRECTION FINDER Application filed December a, 1923. Serial No. 678,096.

This invention relates to direction finders I or compasses of the gyroscopic type, the principal object of the invention being to pro- I vide improved means for controlling a single gyroscope whereby a substantial improvement in accuracy may be obtained. In general, the invention comprises a top-heavy gyroscope provided with a neutralizing pendulum yieldingly connected to the gyro cas 1o ing, and also provided with a thermally controlleddevice adapted to alter the effect of the top-heavy mass sov as to produce the necessary damping efiect.

Where a gyroscope is used as a direction indicator, its operation must be controlled in such a. manner that the gyroscope will precess towards the meridian whenever the gyro axle is inclined to the meridian; and the oscillations of the gyro axle about the meridian must be damped out within a reasonable time. Means must also be provided for preventing the disturbing forces arising from the oscillations of the vehicle (such as a ship) on which the gyro is mounted, from interfering with the accuracy of the indications. The controlling mechanism must therefore perform three distinct functions:

Firstfllhe application of a suitable force to the gyroscope to cause precession towards the meridian when the gyro axle is inclined to the horizontal due to the rotation of the earth. This may be termed the. meridian seeking function.

Second. The checking and ultimate de- 85 struction of the oscillations of the gyro axleabout the meridian within a reasonable time; i. e., the damping function.

Third. The prevention of the disturbing forces arising from the oscillations of the vessel or other vehicle carrying the gyroscope, from interfering with the accuracy of the indications.

For obvious reasons it is most desirable to have all three of these functions performed entirely within the sensitive part or direction seeking element of the compass so that no external agency (such as a follow-up system) need be employed.

. It is well known that a pendulous gyroscope possesses meridian seeking qualities, and it is also true that a't op-heavy gyroscope possesses meridian seeking qualities identical with those of a, pendulous gyroscope, providedthe directionof rotation of the gyroscope in the latter case be reversed. Therefore, other things being equal, either a pendulous or a topeavy gyroscope gives satisfactory results'so far as the meridian seeking function is concerned; and it is to be noted that both of these forms areisubject to precisely the 5 same disturbing forces when the vessel rolls while on an intercardinal direction.

I 'prefer to use a top-heavy gyroscope, in which case the undersirable effects which the disturbing forces arising from the o'scilla- 5 tions of the vessel tend to produce, can be avoided almost entirely by employing a pendulum of such dimensions and arranged in such a manner that the pendulous effect equals and opposes the top-heavy effect when the gyroscope is subjected to these disturbing forces.- In order that the pendulum may perform its intended function without interfering with the meridian seeking function of the gyroscope, the pendulum should be connected to the gyroscope casing b means ,of a slowly yielding connection, such as a dash pot. If the dash pot, or equivalent yielding connection, is properly adjusted, the entire gyrosco e behaves with respect to rapidly reversing orces (such as those caused by the rolling of a vessel) as if it were in neutral equilibrium; however, a sustained inclination of the re axle arising from the earths rotation wil permit the pendulum to return slowly to its vertical position, thus allowing the top-heavy mass to exert its full effect upon the gyroscope which then precesses towards the meridian in the well-known manner. It is thus possible to obtain the the meridian. In order to damp meridian seeking qualities of a top-heavy gyroscope, and at the same time cause the gyrosco to remain in substantially neutral equilibrium with respect to forces produced by oscillations of the vessel.

The damping of the oscillations of the gyro axle about the meridian presents a difcult problem, particularly w ere this funct-ion is to be performed entirely within the sensitive element. In order to appreciate the nature of the conditions under which the damping mechanism must operate, it is helpful to consider the action of a top-heavy gyroscope provided with a'pendulum arra'n ed as above described. When the gyroscope ecomes inclined because of the earths rotation, the pendulum inust return to approximatel its normal position within a short perio of time, for example, within two minutes, thus allowing the top-heavy mass to act on the oscope to process it slowl towards t e oscillations of the gyroscope about t e meridian, it is necessary to decrease the effect of the topheavymass as time oes on, so that the rate of precession will be ecreased when the gyro approaches its meridian position. Therefore, the top-hea mass must slowly recover a part of its initia inclination, thus reducin the moment acting on the gyroscope and ultimatel checking the oscillations about the meri an.

The means by which the effect of the topheavy mass can be gradually decreased In order to effect the proper damping of the system, may be best understood by considerin the articular embodiment of the invention ustrated in' the accompanying drawings The following detailed description and the accompanying drawings disclose the preferred embodiment of the invention and the various objects and advantages of the invention will be apparent upon considering this particular embodiment. In the drawings 1 Fig. 1 is a vertical section'view of my improved gyroscopic compass.

Fig. 2 1s a vertical section view taken on line 2-2 of Fig. 1 showing the details of construction.

Fig.3 is a plan view of the improved gyrosco com ass.

Fig. Y is angnlarged sectional view of a valve mechanism forming a part of the compass illustrated in Figs. 1 to 3, inclusive,

Figs-.5, 6 and 7 are diagrammatic views of the improved oscopic compass, illustrating its mode 0 operation.

Figs. 1 and 3 show the ordinary binnacle 1, supporting a ring 2 by means of a plurality of springs3. A. compass casing 4 is in turn supported by the ring 2 by means of

suitable trunnions

5, 5. The casing 4 is pro.- vided with a glass cover 6,;held in place by ings 26 near each of the a suitable clamping ring 7 which ma be fixed to the casing 4 by means of small olts 8 ,and two

stationar pointers

9, 9 are fixed to the upper part' 0 this casing. The

caspointers

9, 9 to give'direct-ion indications.

The gyroscope proper-is mounted within agyro casing 15, the axle of the gyro being supported in

suitable bearings

16, 16, forming part of the g ro casin This casing 15 is supported wit in the oating casing 11 by means of knife edge supports 17, the easing 15 being mounted so that it may rotate about an axis at right angles to the axis of the gyro wheel.

The gyro wheel and its casing 15 are made top heavy by means of two weights18 and 19 which are 'supported at the free ends of two upright strips of thermostatic metal 20 and-21. These strips are supported within

casings

22 and 23, fixed to the gyro casing 15 in any convenient manner, such as by the

tubes

24 and 25 which serve another purse in addition to fixing the parts together. lectric heating elements 36 are provided within the

casings

22 and 23 for heating the stri s of

thermostatic metal

20 and 21.

It wil be noted that the gyro casing 15 is provided with a pluralit bearings. 16, the pur ose of these openings being to admit air tToht e gyro casing near the center thereof.

e provi d ed with a depending portion 27 which is fixed to the-

tubes

24 and 25 and forms a of small openro casing is open at the bottom, and

partial enclosure for a valve 28. By referring to Fig. 4 it will be noted that

tubes

24 and 25 are separated by a partition 29 and that each of the tubes is 'rovided with an opening facing downwar within the en- 0 osing casing 27. Valve 28 is adapted partially to' cover each of these openings, and to control ,the suppl of air to these pipes in a manner hereina 1' described.

The means for preventin the forces arisirig from the oscillations o the vessel, from a ecting the operation of a roscopic unit, consists of a pendulum in t e form of a yoke 30, supported on the axle of the gyro casing 15 by knife edges 31. The valve 28, above-referred to, is carried b the yoke 30; and this yoke is connected to t e gyro casing 15 b means of two yielding connections in the orm of dash ots 32 and 33. The cylinders of the two ash pots are fixed to the yoke 30 and the pistons of the dash pots'are connected to an irregularly shaped bar 34 (see Fig. 2) by meansof piston rods 35. The bar 34 is fixed to the gyro casing and the piston rods 35 are pivoted to the ends of this bar so that relative movement may take place between the yoke 30 and the casing 15. The dash pots 32 and 33 should be adjusted so that the pendulous yoke 30 will return to its vertical position within, a relatively short period of time after it has been deflected. This yoke should return to substantially its vertical position within approximately two minutes after the yro axis has become inclined by virtue of the earths r0.- tation.

The size and proportions of the yoke 30 should be such that when the yoke and the

weights

18 and 19 are in their normal or vertical positions, the gyro casing is in neutral equilibrium. The

weights

18 and 19 should have no effect on the system until the yoke 30 gets out of alignment with the

weightsupports

20 and 21. When this occurs, the gyro casing is rendered top heavy by the action of the'weights 18 and 19 disposed near the top thereoi. These weights then exert a moment on the gyro casing acting about the horizontal axis through the bearing supports 31, 31; and this moment causes the gyro to precess towards the meridian in the wellknown manner.

Unless the effect .produced by the

weights

18 and 19 is modified in some way, the gyro axle will continue to oscillate about its meridian position and thus render the compass Wholly unsatisfactory. It is necessary to provide some means for counteracting or neutralizing the moment exerted by the

weights

18 and 19, in such a manner that it is graduall diminished. Y

If some moment were to be applied for the purpose of damping the oscillations of the gyro axleabout its meridian position, this moment should always oppose the moment exerted by the

weights

18 and 19, and it should be proportional to the velocity of the gyro axle as it oscillates about its meridian position. When the gyro axle is in either extreme position, its angular velocity is zero and no damping force is necessary. On the other hand, when the gyro axle is crossing the meridian its velocit is a maximum and the opposing damping orce should also be a maximum at this instant.

Since it is true that the efl'ect of a satisfactory damping force of the character above described is virtually to neutralize theefiect of the top-heav mass to a certain extent, it

is conceivable t at the same result might be accomplished by shifting the top-heavy mass or masses (as the case may be) so thatthe moment exerted by the mass is diminished, the diminution of the moment being proportional to they velocity of'the gyro axle. Accordingly, I prefer to construct the compass in such a manner that the to -heavy mass can be shifted toproduce the e ect just described. When the gyro axle is oscillated about the meridian position, the axle is inobtains, more air flows into the casing clined to the horizontal the maximum amount when it crosses the meridian, the axle of course being substantially horizontal when it occupies either extreme position away from its meridian position. This characteristic feature of the gyroscope is utilized in chang ing the positions of the

weights

18 and 19 to produce the desired damping effect.

The manner in which the damping function. is performed may be best understood by considering Figs. 5, 6 and 7 of the accompanying drawings, which illustrate, in an exaggerated manner, the conditions that ex.- ist at several stages in the operation of the damping system. Fig. 5 shows the condition existing when the gyro axle is first inclined to the horizontal, due to the rotation of the earth. The condition represented in this figure is a temporary condition only. The oscillations of the vessel have no effect on the various parts ofthe apparatus and they are not displaced relatively to each other for no moment is created by the oscillations which would tend to cause precession of the gyroscope. When this condition is brought about by virtue of the e'arths rotation, the inclination of the gyroscope axle persists for a considerable time, and the yoke 30 returns to its vertical or normal position as shown in Fig. 6. The

weights

18 and 19 do not re turn to their normal positions because of the sustained inclination of the gyroscope axle,

and therefore these weights exert a moment which causes precession of the gyroscope toward the meridian.

The rotating gyro wheel draws air in through the openings 26 in the gyro casing 15 and expels this air through the open bottom of the casing 15 and the casing extension 27. Part of the air' so discharged from the gyro casing 15 passes into the two

upright casings

22 and 23 through the

pipes

24 and 25. It is to be noted that the Valve 28 in Figs. 2 and 5 is disposed in alignment with the partition 29 which separates the two tubes 2% and 25. This permits the same amount of air to flow into each of the

casings

22 and 23, and for this reason, the heat generated by the heating elements 36 is dissipated to the same extent in each of the

casings

22 and 23 and the temperatures'of both the upright strips of thermostaticmetal and 21 are equal.

When the condition illustrated in Fig. 6 23 than flows into the casing 22, for the reason that the valve 28 has nearly closed the opening in pipe 24, and the port opening into the pipe is almost completely uncovered.

.The effect of this unequal distribution of the air expelled from'the gyro casing is to cool thethermostatic strip 21 and increase the temperature of the thermostatic strip 20. This is due to the fact that the reduced quantity of air flowing into the casing 22 carries away the heat generated within casing 22 at a very slowrate, while the air flowing into the casing 23 carries away the heat enerated therein at an increased rate. he eflect of the unequal temperatures of the

strips

20 and 21 is to cause move toward the vertical. These strips of course carr the

weights

18 and 19 with them and the e ect is to reduce the moment exerted by these weights about the horizontal axis through the supports 31', 31. Figure 7 shows, in exaggerated form, the condition existing after the

weights

18 and 19 have beenmoved to their new ositions. The various parts should be a justed so that the

weights

18 and 19 are deflected from their normal positions the maximum amount when the gyro axle is crossing the meridian, for it is at this instant that the damping'efi'ect should be a maximum.

The use of electrically controlled heating elements within the

casings

22 and 23 makes it'possible to secure a nice adjustment of the several parts, whereby very accurate direction indications can be obtained.

V It is to be observed that a change of temerature due to a-change in atmospheric conitions, produces no undesirable effect on my improved gyro compass. This is true for the reason that when the temperatures of both strips20 and 21are increased the same amountilthese strips will either move toward each 0t er or away from each other, as the case may be.

It is not unusual to connect a penduluos element to a gyro casin by means of dash pots for the (purpose 0 making the casing ndulous an to secure the necessary dampmg efiect, but it will be noted that the yoke 30 of this invention does not make the gyro casing pendulous. It is used for an entirely difierent purpose. Theidash pots 32 and 33 are ad'usted so as to permit the yoke 30 to swing ack to its vertical position in a short period of time, for examp e within ap roximatel two minutes after it has been d fiected. ere a pendulous yoke and a dash pot are used for the purpose of damping the oscillations of the gyro axle and to impart the direction seeking property to the system, the dash t or other yielding connection must be a justed to set very slowly.

This invention comprises a simple arrange ment of inexpensive parts, and possesses the distinct advantage that the various parts can be readily adjusted so as to produce very accurate indications.

The 8126- and proportions of the valve 28 may easily be varied so as to produce any desired ad ustment of the a paratus. The number of moving)parts none that the -wei hts 18 and 19, the thermostatic stri s 20 an? 21,and the various other parts wo d seldom if ever get out of order.

It is to be understood that this invention these strips to is not limited to the particular embodiment illustrated and descri ed, butincludes such modifications thereof as fall within the scope of the appended claims. 1

'I claim:

1. A device of the ty e described, compris ing the combination 0 a dependent weight mounte on eac side of said gyroscope, the said weights being arranged so that they can render the top heavy, and means controlled movement of the gyro axle away from t e horizontal, for moving said weights with respect to said gyrosco e, whereby the oscillat ons of the gyro a e about the meridian are damped.

y 2. A device of the type described, comprising the combination 0' a gyroscope, a thermostatic strip mounted on each side of said gyroscope, a wei ht connected to each strip,-

rosco e, an in-' gyroscope,

the said weights eing arranged so that they can render the roscope top heavy, and means controlled%y movement of the gyro axle away from the horizontal, for changing the temperatures of said strips.

3. A device of the type described, comprising the combination of a gyroscope, a thermostatic strip mounted on each side of said gyroscope, means for heatin said strips, a weight carried by each of sai strips, the said weights being arranged sothat they can render the gyroscope top heavy, and means controlled by movement of the gyro axle away vfrom the horizontal for causing air to flow into close proximity to said strips, to control the temperatures thereof. 1

4. A .device of the type described, comprising the combination ot a gyro wheel, a casing therefor, a thermostatic strip at each side of said casing and carried thereby, means for heating said strips, a weight carried by each of said strips, 0. pendulous-member associated with said gyro casing, and means ineluding an air directing devlce controlled by saidmember for causing air discharged from said casing to come into close proximity to said strips to control the temperature thereof.

5. A device of the type described, comprising the combination of a gyro wheel, a casing therefor, a thermostatic stri on each side of said casing and carried there y, means each of said strips, 9. pendulous member, means for yieldingly connecting this member to said gyro casing, and means controlled by relative movement between the casi and said member for causing air from sai casfor heating said strips, a weight carried by for heating said strips, a weight carried by p I each of said strips, a pendulous member, means for yieldingly connecting said pendulous member with said gyro casing, and means carried by said member for causing air from said casing to flow into said air connect-ions upon relative movement between the member and the casing for the purpose described.

7. A device of the type described, comprising the combination of a gyro wheel, a casing therefor, a thermostatic strip on each side of said casing, a casing surrounding each of said strips,.means Within the casings for said strips for heating said strips, an air connection between said gyro casing and each of the casings enclosing said strips, a weight carried by each of said strips, a pendulous member, means for yieldingly connecting said pendulous member with said gyro casing, and means carried by said member for causing air from said gyro casing to flow into said air connections upon relative movement between the member and casing for the purpose described.

8. A device of the type described, comprising the combination of a gyro wheel, a casing therefor, a thermostatic strip on each side of said casing, a casing surrounding each of said strips, electric heating elements within the casings enclosing said strips for heating said strips, an air connection between said gyro casing and each of the casings enclosing said strips, a weight carried by each, of said strips, a pendulous member, means for yieldingly connecting said pendulous member with ,said gyro casing, and a valve member carried by said pendulous member for causing air from said gyro casing to flow into said air connections upon relative movement between the member and the casing for the purpose described.

9. A device of the type described comprising the combination of a gyroscope having its spin axis normally horizontal, a pendulous member, yielding means connecting said member to said gyroscope to hold the gyroscope in substantially neutral equilibrium, and static means adapted to exert a counter moment to render the gyroscope top heavy when the gyroscope becomes inclined from normal osition, said means being controlled by relative inclinationbetween the member and gyroscope for governing said static means to gradually decrease the moment whereby the oscillations of the gyroscope are dampe 10. A device of the ty e described comprising the combination 0 a gyroscope having its spin axis normally horizontal, a pendulous member, yielding means connecting said member to said gyroscope andad'apted I to exert a moment to hold the gyroscope in substantially neutral equilibrium, and static means adapted to exert a counter-moment for rendering the gyroscope to heavy when it moves out of the position 0 substantial neutral equilibrium, the said means for rendering the gyroscope top heavy being controlled by relative movement between said member and the gyroscope to gradually minimize the moment exerted thereby as the gyroscope precesses toward the meridian, whereby oscillations about the meridian are damped.

11. A device of the type described comprising the combination of a gyroscope" having its spin axis normally horizontal, a pendulous member, yielding means connecting said member to said gyroscope to hold the latter in substantially neutral equilibrium, and means adapted to exert a moment for rendering the gyroscope top heavy when the gyroscope becomes inclined from normal posltion, the said.

pendulous member being adapted to exert a moment, counteracting the moment exerted by the means for rendering the gyroscope top heavy, and thereby lessen the moment when the gyroscope approaches substantially normal equilibrium, whereby oscillations of the gyroscope are damped.

12. A device of the type described comprising the combination of a gyroscope having its spin axis normally horizontal, a pendulous member carried thereby and adapted to hold the gyroscope in substantially neutral equilibrium, means for rendering the gyroscope top heavy when it moves out of a position of substantially neutral equilibrium, yielding means between said member and the gyroscope permitting relative movement between them to cause said member to exert a moment on'said gyroscope for a predetermined period of time after the gyroscope spin axis has become inclined to the horizontahand means controlled by relative movement between the member and the gyroscope for governing said means for renderin the gyroscope top heavy to damp the oscillations of the gyroscope spin axis about the meridian.

13. A device of the type described comprising the combination of a gyroscope having its spin axis normally horizontal, a pendulous member carried thereby and adapted to hold the gyroscope in substantially neutral equilibrium, means carried by said gyroscope for rendering the same top heavy when it moves out of a position of substantially neutral equilibrium, yielding means between said member and said gyroscope per-' mitting relative movement between them for a predetermined period of time after the gyroscope and pendulous member have become inclined, and means controlled by the said relative movement to govern said first named means for varying the countermoment,

exerted thereby to damp the oscillations of the gyroscope spin axis. i v

14. A device of thetype described comprising the combination of a gyroscope havin its spin axis normally horizontal, a pendu 011s member yieldingl connected to said gyroscope and 'adapte to hold the same in a subetentially neutral equilibrium, static means adapted to exert a moment on said gyroscope by renderin the same top heavy when it moves out o a position of substantially neutral equilibrium, and means controlled by relative movement between the gyroscope and said. pendulous member upon inclination thereof for reducing the moment exerted by said first named means whereby the oscillam tions of the gyroscope spin axis are damped.

Intestimon whereofIefiixm si ature. 7 AB PATTERSO AVIS.